Display panel with a graphical user interface



FIG. 1 is a front view of a display panel with a graphical user interface showing a first embodiment of our design;

FIG. 2 is a front view of a display panel with a graphical user interface showing a second embodiment thereof; and

FIG. 3 is a front view of a display panel with a graphical user interface showing a third embodiment thereof.

The broken lines, including all text, illustrate portions of the graphical user interface or mixed reality environment and form no part of the design. 

CLAIM The ornamental design for a display panel with a graphical user interface, as shown and described. 